Precise positioning of electrodes on a patient's body is indispensable for a large number of medical examinations. A prominent example is an ECG (electrocardiogram) examination and a bio-impedance measurement.
If such an examination is to be carried out in a home environment, there may be no medically trained person present, so the patient, or a not medically trained person, has to take over tasks, which may require certain medical and technical background knowledge, e.g. for placement of electrodes.
In heart failure examinations and/or chronic heart failure treatment, it may be required to perform a daily bio-impedance measurement comprising the positioning of a number of electrodes on the patient body by the patient at home. In order to obtain meaningful results from such repetitive measurements, it is indispensable that each electrode is placed at substantially the same position for every measurement.
For example, the bio-impedance technique is safe, non-invasive and reproducible provided that the electrode placement is not changed. It has been shown for using transthoracic electrical impedance measurement for detecting pulmonary edema, that the effects of variations in electrode positioning limit the value of serial intermittent bio-impedance measurements. Differences of about 5Ω have been reported, when the electrodes were moved 6 cm.